Load: The lights or appliances run by your electrical system. The amount of electrical power being consumed at any given moment.

Kilowatt: A thousand watts

Megawatt: One million watts, 1,000 kilowatts

Off-grid: See stand-alone.

Peak watts: The amount of power a photovoltaic device will produce at noon on a clear day with sun approximately overhead when the cell is faced directly toward the sun.

Photovoltaic: Capable of producing a voltage when exposed to radiant energy, especially light.

Photovoltaic array: A group of solar electric panels connected together.

Photovoltaic cell: The basic building block in photovoltaic systems. Sometimes called “Solar Cells.”

Photovoltaic effect: The conversion of sunlight absorbed by a solar cell directly into electricity.

Photovoltaic module: A solar electric panel

Power: See Watt

Semiconductor: Any material that has limited capacity for conducting an electric curre.

Stand-alone: An isolated photovoltaic system not connected to a utility electric grid.

Utility: An electrical supplier serving electric power to customers (such as APS or SRP in Arizona)

Voltage: A measure of the force or “push” given the electrons in an electric circuit, a measure of electric potential.

Voltage regulator: An electrical device used to keep voltage at predetermined levels.

Watt: A unit of Power, one watt is the rate at which work is done when one ampere (A) of current flows through an electrical potential difference of one volt (V). Items like light bulbs are rated in watts. Power is the rate at which energy is generated or consumed and hence is measured in units (e.g. watts) that represent energy per unit time.

Watt-hours: A unit of Energy, defined as power over a time interval. One watt of power for one hour is one Watt-Hour. Often used with the prefixes Mega and Kilo for 1-million and 1-thousand.